The aim of the present invention is to provide a process for checking the condition of the roads in winter and more particularly during periods of frost or snowfall.
It relates more particularly to a process for determining the amount of chemical deicer present on a road.
In order to ensure that the roads are in good condition during periods of frost or snowfall, and in particular to preserve an adequate grip thereon, it is common practice to spread chemical deicers, such as, for example, an alkali metal chloride or alkaline earth metal chloride, urea, alcohols and the like, on the roads.
Although these chemical deicers can be spread on the roads after a slippery layer of frost, ice or snow has formed thereon, in order to melt the layer, they generally prove more active, however, when they are spread as a preventive measure, that is to say before a slippery layer of this kind has had the time to form. This practice exhibits the additional advantage that it permanently prevents the formation of a layer of ice, frost or snow on the roads, which is obviously likely to increase the safety of the users.
However, the spreading of chemical deicers as a preventive measure exhibits the disadvantage that they are gradually removed from the roads by the effect of traffic and wind, and also by run-off during precipitation, with the result that it proves necessary to carry out periodic spreading operations. It is therefore important to be able periodically to check whether the amount of chemical deicer present per unit area of the road is adequate for the safety of the users. For this purpose, it has already been proposed to measure the electrical resistance of the film of chemical deicer which covers the road (H.sub.2 O-Tijdschrift voor watervoorziening en afvalwaterdeling, Volume 10, Nov. 24th, 1977, page N96; French Pat. No. 2,061,899). Although it is easy and rapid, this known checking process has proved unreliable in practice because it is incapable of ensuring a precise and reproducible measurement of the amount of deicer present on the road.